Solid organs (brain, liver, spleen, kidney, pancreas, etc.) have a large number of small blood vessels, resulting in such a structure that the solid organs may bleed wherever the solid organs are cut. In particular, as soft solid organs having a considerable number of capillary blood vessels, liver, pancreas, spleen, and kidney are given. Besides, the solid organs are not strong tissues unlike luminal organs although the solid organs are harder than soybean curd. When a transducer is brought into contact with the solid organ, the solid organ is sonicated, and hence the cell tissue thereof falls apart so that the solid organ is cut while being punctured.
In the case of thinly excising organ tissues for excision of the above-mentioned organs, an ultrasonic coagulation cutter and a radio-frequency coagulation cutter have mainly been used. However, in the case of excising an organ site having a depth of 1 cm or more, blood vessels thereof are thick, and hence the ultrasonic coagulation cutter and the radio-frequency coagulation cutter cannot be used. Thus, in the case of excising a deeper organ site, an ultrasonic aspirator (CUSA, etc.) using a high-frequency wave or ultrasonic vibration (cavitation) has been used. However, even with those tools, slight bleeding cannot be suppressed sufficiently. Further, in the cirrhotic liver tissue in which the liver tissue is hard, in spite of the fact that liver cancer is, in particular, liable to occur, the resection performance of the ultrasonic aspirator is insufficient. Accordingly, in actuality, surgical tools cannot sufficiently excise the cirrhotic liver that is most liable to bleed and is found in many cases.
Further, commercially available medical instruments are configured to destroy organ tissue with a transducer, inject water into the destroyed organ tissue so as to wash the organ tissue away, and aspirate the organ tissue. This operation is repeated to resect a solid organ in a fine blood vessel portion. The transducer includes an ultrasonic transducer for generating an ultrasonic wave and a transmission member for transmitting, to a target, the ultrasonic wave generated by the ultrasonic transducer (Patent Literature 1).
In a surgical tool having a microwave irradiation function, a needle-like probe for performing microwave irradiation outputs a microwave only from a tip end thereof. On the other hand, the inventors of the present invention have confirmed that a surgical tool having a microwave irradiation function with halved coaxial cable-like structures is capable of outputting a microwave even in a long line extending from the center to the outside along the halved structures (Patent Literature 2).
However, in actuality, there is no surgical tool capable of concurrently performing both the destruction of an organ, in particular, a solid organ and the hemostasis by the coagulation of tissue.
A surgical tool using a transducer and a high-frequency current in combination has been reported. This surgical tool is a surgical instrument “comprising: a hand piece equipped with a treatment section arranged at the tip side thereof to treat living body tissue and including a probe to be supplied with a high frequency current according to a directive and an ultrasonic transducer rigidly secured to the probe and adapted to ultrasonically oscillate the probe; a high frequency drive circuit which supply a high frequency current to the probe; and an ultrasonic transducer drive circuit which drive the ultrasonic transducer, the ultrasonic transducer drive circuit being adapted to control the amplitude of ultrasonic oscillations at the treatment section according to the magnitude of the impedance value as detected by the high frequency drive circuit at the time of outputting a high frequency current” (Patent Literature 3). However, this instrument is provided only for the purpose of preventing the burning of living tissue, which may be caused by a scalpel top electrode.